package org.itstack.demo.design;

/**
 * 懒汉模式 线程不安全
 */
public class Singleton_01 {

    private static Singleton_01 instance;

    private Singleton_01() {

    }

    public static Singleton_01 getInstance() {
        if (null != instance) {
            return instance;
        }
        return new Singleton_01();
    }
}
